Food mixer



JQIL 25, 1943. M. J. LANDGRAF FOOD MIXER Filed arch 25, 1940 2Shootsheet 1 ATTORNEYS JUL 26, 1943- l M. J. LANDGRAF FOOD MIXER Filedarch 23, 1940 2 Sheets-Sheet 2 Patented Jan. 26, 19,43

FOOD

Myron J. Indgraf,

Chios! Henry J. Goidblatt,

o, lli.. assigner to Chioago,lll.

Application March 28, 1940, Serial No. 925.530

'i Claims. (Cl. 259-108) Hy invention relates in general to mixingdevices and more in particular to supporting and driving connectionsbetween the bowl and base 'which carries the motor.

Mixing and liquefying devices of the general type disclosed in my priorapplications Serial No. 270.319 issued as Patent No. 2,278,125 on Mar.81, 1942 and 270,320 issued as Patent No. 2.284.155 on May 26, i942,nled April 27, 1939, operate at relatively high speed with the resultthat there is a very strong centrifugal action to the material in thebowl and a pronounced tendency for the bowl body to move with respect tothe base which carries the motor. Those skilled in the art are wellaware of this situation and the result has been that the bowl has beenattached to and supported on the base by means which resulted in awedging and clamping action against the bottom of the bowl. The driveconnection between the two shafts, one carried by the base and the othercarried by the bowl portion, has also been such as to cause a relativelyfirm engagement. In other words, because of the assumed tendency of thebowl to lift as well as rotate with respect to the base, the bowl hasbeen mounted and gripped in place to cause an attachment almost as if itwere constructed with the base, notwithstanding the fact that it had tobe removable from the base to permit pouring the contents from the bowl.This resulted in the necessity of maintaining Very close dimensions and,in general, replacing the bowl in exactly the position which it had whenremoved from tile base.

I have found that by providing a loose but relatively resilient supportfor the bowl and a loose but relatively resilient drive between theshaft carried by the base and the shaft journaled in the bottom of thebowl, I am able entirely to overcome the problems which have heretoforebeen encountered while at the same time avoiding any tendency for thebowl to become unstable and have any objectionable movement with respectto the base during operation. The bowl may be placed on the base in anyone of several positions, whatever the relative positions of the shaftconnecting mechanism may be. By suitable structure utilizing theprinciple of a loose but adequate support and drive connection, I notonly secure definite advantages so far as the use of the mixer isconcerned, but I am also able to simplify construction and assembly ofparts with a concomitant saving in manufacturing costs.

In the accompanying drawings, I illustrate one embodiment of theinvention, wherein Fig. 1 is an elevational view. the upper part of thebowl being broken away to illustrate a structural feature:

Fig. 2 is an enlarged fragmentary vertical sectional view taken throughthat portion of the mixer where the bowl is supported on the base:

Fig. 3 is an irregular bottom plan section taken on the line 3-1 of Fig.2, looking in the direction of the arrows;

Fig. 4 is a fragmentary sectional view tak ontheline44ofFlg.2;

Fig. 5 is an enlarged fragmentary elevational view showing the driveconnection between the shaft carried by the base and the shaft carriedby the bowl;

Fig. 6 is an enlarged fragmentary sectional view showing some of thestructural features of the drive mechanism; and

Fig. 'l is a sectional view taken on the line 1-1 of Fig. 6, looking inthe direction of the arrows, the lower drive shaft also being includedin the view in order to illustrate the manner of its engagement.

In general, the device of my present invention utilizes the principlesand general structural features disclosed in my prior co-pendingapplications. I utilize a base indicated generally by the referencecharacter I0, and mixing bowl indicated generally by the referencecharacter Il. The base I0 houses a suitable motor, not shown, driving ashaft l2 through which power is delivered to the mixing mechanismcarried by the bowl in a manner to be described. Suitable currentcontrol mechanism, 'such as a switch i3, is carried by the base wherebyto operate the motor at a selected speed determined by the operationbeing carried out. The bowl is-readily removable from the base andfunctionally associated therewith, materials to be mixed or liqueedbeing introducible into the bowl, as will be described. For the purposeof bringing out the association between the mixing bowl and base, Ishall rst describe the structure of that part of the base with which thebowl is associated.

The base comprises a housing member I4 having a plurality of equallyspaced internally projecting lugs I6. Above the base, a cover member I1is provided comprising in general a portion of a sphere so far as itsshape is concerned, although it may have a modified appearance asdetermined by the design. The cover member I'i is provided with a numberof equally spaced integral legs Il corresponding in position to the lugsI6. Above the cover member I1, and spaced therefrom, is a ,ring member2| having a plu-V rality of equally spaced leg members 22. As appearsparticularly clear from Fig. 2, these leg members 22 flare outwardlyslightly and have their bottom surfaces shaped to correspond to thecontiguous upper surface of the cover member I1. The number of legs 22is the same as the number of legs I8 and lugs I6, so that machine screws23 extending upwardly through apertures in the lugs I6 and legs I8 maybe threaded into bottom apertures in the legs 22 to form an assemblyincluding the housing I4, the cover member I1, and ring member 2l. Theseparts are all of metal according to the preferred structure.

The ring member 2|, with a resilient supporting insert which will now bedescribed, forms a generally cup-shaped loose support for the bowl II.The resilient supporting insert, preferably formed of relatively liverubber, such as a semisoft vulcanizedr rubber compound, comprises a ringportion 24 extending somewhat above the ring portion 2| and shaped withan annular upper flange projecting over the upper edge of the ringmember 2|. At the position of each leg 22, the resilient member isprovided with internal supporting projections 26 as shown, from thelower edge of which relatively small, irregular projections 21 extenddownwardly. These projections have a relatively narrow intermediateportion and a. relatively broader terminal portion. The legs 22 have anannular opening through which the projection 21 protrudes together withedge slots 28 communicating with the opening. By utilizing the edge slot28, the projection 21 may be inserted in the position shown in Fig. 2(the relationship also appears clear from Fig. 3) so that the resilientsupporting insert comprising the ring 24 is substantially firmlyassociated with the supporting ring 2|. The upper portion of the covermember I1 is provided with a slight depression as shown in Fig. 2 ateach position of the projection 21, so that, when the machine screws 23are tightened, the resilient supporting member is wedged between theupper portion of the cover member I1 and the lower portion of the legs22 to prevent withdrawal of the resilient supporting member. At oneposition, the resilient ring 24 has an internally extending radialprojection 29, and immediately adjacent this projection and on the upperedge of the ring member a relatively small indicating projection 3l. Theindicating projection 3| may be formed a different color than theremaining portion of the resilient ring 24.

From the above description, it will be clear that the resilient portions24 and 26, with the metal portions including the ring member 2|reinforcing them, form in general a cup-like upper recess in which thebase of the mixing .bowl II may be inserted in such a way that the baseof the mixing bowl is loose around the periphery, and the lower edgethereof merely rests upon the internally extending supportingprojections 26. From Fig. 2, it will be clear that there is ample spacebetween the outside of the bowl andthe inside surface of the ring 24 sothat, even allowing for some manufacturing tolerances, the bowl willalways be loose within its support on ythe base. With the exception of aplurality of edge recesses 32 on the bowl, the lower edge is uniform,regular and unbroken. Thus the bowl may be set in any position in whichone of the edge recesses 32 coincides with the location of theprojection 29.

The bowl carries an impeller 33' carried by a shaftn34, the shaft 34being journaled in supporting and sealing mechanism in the generalmanner described in my prior applications. The bottom recess 36 in themixing bowl provides space for a specially designed clutch mechanismcooperating with a clutch mechanism forming a part of the drive shaftl2. The arrangement is such that, independently of the position of thelparts, a driving connection will be established by the mere act ofinserting the bowl in position on the base, and means is provided forproducing an adequately resilient engagement between the parts whilestill maintaining positive drive conditions.

Referring now rst to the driving member of the clutch arrangement, thisutilizes a disk 31 secured to the bottom of the shaft 34 and -carrying apair of downwardly projecting clutch members 38. Each clutch membercomprises a stud 39 carried by the disk 31, a spring 4|, and a speciallydesigned nut 42. The stud 39 has a shoulder 43 over which the endconvolution of the spring engages, and the nut 42 has a cut-away portionwhich engages within a convolution of the spring at the other end, thenut, however, having a portion which engages over the end edge of thespring so that the spring is held taut between the face of the disk andone edge of the specialy nut 42. In actual practice, Athe spring 4| iswound with its convolutions close together. The result of theconstruction is that, if there is pressure against the side of thespring intermediate the ends thereof, the spring as a body will bedeformed slightly as a result of the pressure but will always tend toresume the position shown in the drawings.

The drive shaft I2 is journaled in a special attaching and sealingassembly 44 which lies within a generally cup-shaped upper recess in thecover member I1. The upwardly projecting end of shaft I2 carries adriving pin 46. 'Ihe parts are so constructed and arranged that thedriving pin 46 engages against the edge of the spring members 4|approximately at their midpoints as shown in Fig. 5. If a bowl isremoved and then later set back on the base without in the meantimemoving any of the drive parts, the parts will always occupy a positionwith the driving pin projecting at some angle between the two downwardlyprojecting clutch members 38. Should any of the parts be turned,however, it may occur that the driving pin 46 will be substantially deadin line with the axis of the studs 39. Under these circumstances,however, en-

gagement will still take place because the lower end face of the nut 42is rounded and, of course, the driving pin 46 is rounded. The parts,therefore, will be moved relative to each other so that the bowl may beinserted into its final position and the parts will occupy the positionshown in general in Fig. 5.

In Fig. 1, I illustrate a special cover arrangement wherein a cover 41,preferably formed of semi-soft rubber, has a portion extending over thetop edge of the bowl and an annular portion 43 extending within the bowlwhereby to hold the cover rmly in position. A round cup-like upperprojection 49 is continuous with an opening formed through the main bodyof the cover. The cup-shaped portion is provided with a separate cover52, such as a stainless steel cap or the like. By this arrangement, thebowl may be kept covered during operation and only the cap 52 rethepropeller slightly, producing an even and.

smooth application of power. and also permits some shifting of the bowlon its support to improve the alignment. For example, should be bowl beslightly tipped due to the fact that one edge has not seated on thesurface of the support comprising the projections 2l, the bowl may rightitself during operation. If it does not right itself entirely, theoperation maystill continue, the driving connections functioningpartially as a universal joint. For this and other reasons, the springportion preferably comprises stainless steel wire, and the driving pinis case hardened. Other types of resilient connections may be used, suchas rubber, but the useful life is much less than with my construction.

While the drive cushions the action of the propeller, still there is atendency of the propeller to throw materials upwardly, particularlyduring starting. The combination of the special cover construction andresilient drive inhibits entirely the throwing of material from thebowl. The cap l2 may be removed and vegetable or like materialintroduced through the opening 5I while the propeller is being operated.

What I claim Vas new and desire to protect by Letters Patent of theUnited States is:

1. In a food mixer of the character described, a base having as a bowlsupport a generally cupshaped member of resilient material, a mixingbowl having a lower portion adapted to set loosely in said cup-shapedmember, means effective at more than one position of the bowl forpreventing turning of said bowl with respect to the base, a mixing andcommuting member within the bowl, and means responsive to associatingthe mixing bowl and base for connecting said mixing and comminutingmember to a motor shaft journaled in said base, said last-mentionedmeans comprising a pair of spaced resilient members carried by a shaftJournaled in said bowl, and a pin transversely extending through saidmotor shaft and engageable between said spaced resilient members.

2. In a food mixer, a base carrying a motor driven shaft, a bowl havinga vertical impeller shaft journaled in the base thereof, to which shafta comminuting propeller is secured within the bowl for comminutingvegetables and the like, and a clutch member secured to the shaft belowthe bowl comprising two vertically positioned resilient drive membersspaced substantially equal distances from the axis of rotation, acup-like, resilient, loose support for the bowl on the base wherein thebowl is adapted to set loosely enough to be permitted to adjust itsposition, means to prevent the bowl from turning relative to saidcup-like resilient support, and a pin extending radially from the motordriven shaft adapted to engage sides of said resilient drive members,each said resilient drive member comprising a coil spring, the adjacentconvolutions of which are substantially in contact, and means forsupporting end convolutions of such spring, said pin en gaging againstintermediate convolutions.

3. In a food mixer, a base carrying a motor driven shaft, a bowl havinga vertical impeller shaft Journaled in the base thereof, to which shafta comminuting propeller is secured within the bowl for comminutingvegetables and the like, and a clutch member secured to the shaftbelowthe bowl comprising two vertically pomtioned resilient drive membersspaced substantially equal distances from the axis of rotation. acup-like, resilient, loose support for the bowl on the base wherein thebowl is adapted to set loosely enough to be permitted to adjust itsposition, means to prevent the bowl from turning relative to saidcup-like resilient support, and a pin extending radiailyfrom the motordriven shaft adapted to engage sides of said resilient drive members,each said resilient drive member comprising a coil spring, the adjacentconvolutions of which are substantially in contact, and means forsupporting end convolutions of such spring. said pin engaging againstintermediate convolutions, said means for supporting end convolutions ofthe spring comprising a pin having a base engaging one end convolution,and a nut engaging the other end convolution, said nut having an exposedsurface rounded to prevent engagement against said pin when the bowl isplaced in position in the cup-like support.

4. A drive connection adapted for connection of the drive shaft anddriven shaft of a mixing device of the character described, said driveconnection comprising a shaft, a disc axially secured to one end of saidshaft, a pair of pins secured to said disc in parallel relation to saidshaft and equally spaced from the axis of rotation thereof, springssurrounding said pins having convolutions substantially in mutualcontact, said springs supported in spaced relation to said pins, asecond shaft in alignment with the first shaft, and a pin extendingradially through said second shaft and between said first-mentioned pinsand adapted to engage said springs intermediate their ends.

5. A drive connection adapted for connection of the drive shaft anddriven shaft of a mixing device of the character described, said driveconnection comprising a shaft, a disc axially secured to one end of saidshaft, a pair of pins secured to said disc in parallel relation to saidshaft and equally spaced from the axis of rotation thereof, springssurrounding said pins having convolutions substantially in mutualcontact, said springs supported in spaced relation to said pins, asecond shaft in alignment with the first shaft, and a pin extendingradially through said second shaft and between said first-mentioned pinsand adapted to engage said springs intermediate their ends, saidmst-mentioned pins having a shoulder near their points of attachment tosaid disc, and having a nut threaded on the projecting end thereof, saidnut having a recess forming an annular shoulder, each said spring havingits end convolutions engaged around said shoulders, and the springsbeing clamped between the said disc and nuts, whereby to hold saidsprings in spaced relation to said pins in the manner and for thepurpose described.

` 6. In a food mixer comprising a base carrying a motor and drive shaft,and a removable bowl and shaft Journalled through its bottom and adaptedto be brought into driving engagement with said motor drive shaft, thecombination of v a cup-like resilient loose support for said bowl onsaid base, and a loose resilient connection between said motor driveshaft and said propeller shaft, said loose resilient connectioncomprising a transverse pin carried by one shaft, and a pair of spacedresilient members carried by the other shaft between which said pin isadapted to en- 838e.

7. In a food mixer comprising a base carrying a motor and drive shaft,and a removable bowl carrying a mixing and comminuting propeller andshaft journalled through its bottmn and adapted to be brought intodriving engagement with said motor drive shaft, the combination of l.cup-like resilient loose support for said bowl on said base, and a looseresilient connection between said motor drive shaft and said propellershaft. said loose resilient connection comprising transverse pin carriedby one shaft, and a pair of spaced resilient members carried by theother shaft between which said pin. is adapted to engage, each saidresilient member comprising a coil spring having its axis in alignmentwith but displaced from the axis of said shafts, and means forsupporting end convolutions, the pin engaging the spring at a pointintermediate said end convolutions.

MYRON J. LANDGRAP..

